In this video we have a magician guy doing a card trick. He has four queens in his hand facing the camera and audience. He shakes his hand four different times and each time one of the cards turns from face out to back out (so you can no longer see the card). Once all cards are back out he shows all the cards and they are four aces now. As far as I can tell the way he does the trick is one of the queens has the four Aces as part of it's stack. Each time he shakes the cards he uses his finger to move the face forward card into the central pile of cards in his hand revealing the back faced card. When he moves the first back facing card from the bottom to the front top of the cards is what gives it away.